How work the biss key

Hello i need some information about Biss key.

F 75341FFF 01 DA87B314AA92D20E ;GCUK Enc 4 JSC SPORT FEED(3.1∞E)

how to make up the key?
What the "F" is ?
the first 4 hex digits(7534) indicate what?
subsequent ones (1FFF) ?
where they enter these keys on dreambox?
Thank's